Plasma processing apparatus and plasma processing method

ABSTRACT

A plasma processing apparatus for processing an object to be processed using a plasma. The apparatus includes a processing chamber defining a processing cavity for containing an object to be processed and a process gas therein, a microwave radiating antenna having a microwave radiating surface for radiating a microwave in order to excite a plasma in the processing cavity, and a dielectric body provided so as to be opposed to the microwave radiating surface, in which the distance D between the microwave radiating surface and a surface of the dielectric body facing away from the microwave radiating surface, which is represented with the wavelength of the microwave being a distance unit, is determined to be in the range satisfying the inequality 0.7×n/4≦D≦1.3×n/4 (n being a natural number).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a plasma processing apparatus and aplasma processing method for processing an object to be processed suchas a semiconductor substrate or the like with a plasma excited byradiating a microwave.

2. Description of Related Art

In a work for manufacturing a semiconductor device, a surface qualitymodifying process for modifying the surface material quality bynitriding or oxidizing the wafer surface, an ashing process for removingresist, a layer forming process for forming a thin layer by depositingmaterials such as an insulating material or the like on the wafersurface and an etching process for processing the thin layer formed onthe wafer surface into minute patterns are carried out. Attention hasbeen paid to an RLSA (Radial Line Slot Antenna) plasma processingapparatus as an apparatus for carrying out these processes.

An RLSA plasma processing apparatus comprises a processing chamberhaving an opened upper surface, and a dielectric plate disposed asclosing the opened upper surface of the processing chamber. A cavitydefined by the processing chamber and the dielectric plate serves as aprocessing cavity for plasma processing a semiconductor wafer as anobject to be processed. Provided in the processing cavity is a waferstage for mounting and holding a semiconductor wafer thereon. Further,disposed above the dielectric plate is a radial line slot antenna forradiating a microwave through the dielectric plate into the processingcavity.

For example, in the case of nitriding the surface of a semiconductorwafer using such an RLSA plasma processing apparatus, first, thesemiconductor wafer is mounted on the wafer stage with the surface ofthe semiconductor wafer directed upwardly. Next, a process gas (forexample, Ar/NH₃) is supplied into the processing cavity, and thereaftera microwave is radiated from the radial line slot antenna toward theprocessing cavity. Thereby, a plasma of the process gas is generated inthe processing cavity, and the surface of the semiconductor wafermounted on the wafer stage is nitrided by the generated plasma.

The radial line slot antenna has a number of slots formed so as to bedistributed in the whole region of the lower surface of the antenna, sothat the microwave is radiated from the number of the slots.Consequently, in an RLSA plasma processing apparatus using such a radialline slot antenna, since a microwave can be radiated substantiallyuniformly in the processing cavity, a plasma of a process gas can beuniformly generated. Therefore, it is expected that the surface of asemiconductor wafer can be uniformly processed with the plasma.

However, in a conventional RLSA plasma processing apparatus, since thedensity of a plasma generated in the processing cavity is low, theprocessing rate is low. Consequently, such a conventional RLSA plasmaprocessing apparatus cannot be used for manufacturing a semiconductordevice in practice.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a plasma processingapparatus capable of generating a high density plasma.

Another object of the present invention is to provide a plasmaprocessing method capable of processing an object to be processed with ahigh density plasma.

A plasma processing apparatus according to the present invention is onein which a microwave is radiated from a microwave radiating antenna to aprocessing cavity containing an object to be processed and a process gastherein, thereby to excite a plasma at a plasma exciting surface spacedfrom a microwave radiating surface of the microwave radiating antenna bya predetermined distance, so that the object is processed with theexcited plasma. In a plasma processing apparatus according to thepresent invention, a dielectric body is provided so as to be opposed tothe microwave radiating surface, and the distance D between themicrowave radiating surface and the surface of the dielectric bodyfacing away from the microwave radiating surface, which is representedwith the wavelength of the microwave being a distance unit, isdetermined to be in the range satisfying the following inequality0.7×n/4≦D≦1.3×n/4 (n being a natural number)(preferably in the range of 0.8×n/4≦D≦1.2×n/4, and more preferably inthe range of 0.9×n/4≦D≦1.1×n/4).

The distance D is preferably determined in the range of0.7×n/2≦D≦1.3×n/2 (more preferably in the range of 0.8×n/2≦D≦1.2×n/2,much more preferably in the range of 0.9×n/2≦D≦1.1×n/2).

Further, it is preferable that a standing wave of the microwave isformed between the microwave radiating surface and the plasma excitingsurface, and a plasma is excited at the plasma exciting surface by beingsupplied with energy from this standing wave of the microwave.

According to the present invention described above, by setting thedistance D between the microwave radiating surface and the plasmaexciting surface (substantially coinciding with the surface of thedielectric body facing away from the microwave radiating surface), whichis represented with the wavelength of the microwave being a distanceunit, in the range satisfying the above-mentioned inequality (namely, tobe a value near n/4, and more preferably a value near n/2), a favorablestanding wave can be formed in the region between the microwaveradiating surface and the plasma exciting surface, and thereby a highdensity plasma can be generated in the processing cavity. Consequently,such a plasma processing apparatus can be appropriately used formanufacturing a semiconductor device or the like.

It is preferable that a dielectric plate is interposed between themicrowave radiating surface and the plasma exciting surface. In thiscase, if the distance between the dielectric plate and the microwaveradiating surface is minute, the thickness d of the dielectric plate maybe determined in the range satisfying the following inequality0.7×n/4≦d≦1.3×n/4 (wherein d is a thickness represented with thewavelength of the microwave being a unit),(preferably in the range of 0.8×n/4≦d≦1.2×n/4, and more preferably inthe range of 0.9×n/4≦d≦1.1×n/4).

In the above-mentioned case, the thickness d of the dielectric plate isfurther preferably determined in the range of 0.7×n/2≦d≦1.3×n/2, (morepreferably in the range of 0.8×n/2≦d≦1.2×n/2, and much more preferablyin the range of 0.9×n/2≦d≦1.1×n/2). The above-mentioned microwaveradiating antenna may be a radial line slot antenna provided with anumber of slots for radiating a microwave formed and distributed in themicrowave radiating surface thereof. In this case, it is preferable thata part of the number of slots is closed so that a plasma generated inthe processing cavity is uniform in a plane.

With this structure, by closing a part of the slots formed in the lowersurface of the radial line slot antenna to control the strengthdistribution of a microwave radiated from the radial line slot antenna,the uniformization in a plane of the density distribution of the plasmagenerated in the processing cavity as well as the heightening of theplasma density can be achieved. Thereby, it is possible to apply asubstantially uniform plasma process to a surface of an object to beprocessed in a shorter time than that by a conventional apparatus.

The foregoing and other objects, features, aspects and advantages of thepresent invention will become more apparent from the following detaileddescription of embodiments of the present invention given with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic sectional view showing a construction of a plasmanitriding apparatus according to an embodiment of the present invention.

FIG. 2 is a view showing a lower surface of a radial line slot antenna.

FIG. 3 is a graph showing the density distributions of ion currentincident on the surface of a semiconductor wafer (a) when the thicknessd2 of the dielectric plate is set to be 30 mm and (b) when the thicknessd2 of the dielectric plate is set to be 20 mm (in the case of theconventional apparatus).

FIG. 4 is a graph showing the density distributions of ion currentincident on the surface of a semiconductor wafer W (a) in the case ofnot closing any slot pair, (b) in the case of closing ⅙ of the slotpairs arranged in the outermost peripheral part, and (c) in the case ofclosing ⅓ of the slot pairs arranged in the outermost peripheral part.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a schematic sectional view showing a construction of a plasmanitriding apparatus according to an embodiment of the present invention.The plasma nitriding apparatus is constructed to modify the quality of asurface of a semiconductor W as an object to be processed to a nitride,and used, for example, in a step for modifying a surface of asemiconductor consisting of Si (silicon) to Si₃N₄ to form an insulatinglayer, or the like.

The plasma nitriding apparatus comprises a cylindrical processingchamber 1 having an opened upper surface and a closed bottom. Adielectric plate 2 made of e.g. quartz is provided at the upper portionof the processing chamber 1 as closing the opened upper surface of theprocessing chamber 1, so that a sealed processing cavity 3 is definedbelow the dielectric plate 2. Within the processing cavity 3, a waferstage 4 is disposed on which the semiconductor wafer W is mounted andheld. Further, a gas introducing pipe 5 for introducing a process gasinto the processing cavity 3 is connected to a side wall of theprocessing chamber 1. As the process gas, for example, Ar/NH₃, Ar/N₂/H₂or the like can be used.

Above the dielectric plate 2, a radial line slot antenna 6 is providedat a position spaced with a distance d1 from the upper surface of thedielectric plate 2 and in opposition thereto. The radial line slotantenna 6 is a plate-shaped antenna having therein an insulating platecapable of transmitting microwaves. In the lower surface of the radialline slot antenna 6, a number of slot pairs P are concentricallyarranged as shown in FIG. 2. Each slot pair P comprises a pair of slotsS1, S2 oriented in two directions intersecting with each otherrespectively. These slots S1, S2 form substantially T shape with beingspaced from each other with a distance corresponding to ¼ of thewavelength λg of a microwave in the radial line slot antenna 6 (¼ guidewavelength=¼ λg).

On the other hand, connected to the upper surface of the radial lineslot antenna 6 is a microwave guide 7 for guiding a microwave oscillatedfrom an unshown microwave oscillator to the insulating plate. As themicrowave guide, e.g. a coaxial microwave guide can be used.

In the case of nitriding the surface of the semiconductor wafer W, tobegin with, the semiconductor wafer W is mounted on the wafer stage 4with the surface thereof directed upwardly. Then, an atmosphere in theprocessing cavity 3 is exhausted by an unshown exhausting mechanism.After the processing cavity 3 becomes in a substantially vacuum state, aprocess gas is introduced through the gas introducing pipe 5 into theprocessing cavity 3. Thereafter, with the processing cavity 3 beingfilled with the process gas, a microwave having a frequency of, forexample, 2.45 GHz is generated from the unshown oscillator, and themicrowave is transmitted through the microwave guide 7 in TEM mode to beintroduced into the radial line slot antenna 6.

The microwave introduced into the radial line slot antenna 6 istransmitted through the insulating plate in the radial line slot antenna6, and in the midway thereof, the microwave leaks from the slot pairs Pto be radiated toward the dielectric plate 2, and further, after passingthrough the dielectric plate 2, it is radiated to the processing cavity3. A plasma of the process gas in the processing cavity 3 is excited bythe energy of the microwave radiated to the processing cavity 3, and thesurface of the semiconductor wafer W is processed by the plasma of theprocess gas.

When the electron density in the plasma generated in the processingcavity 3 becomes equal to or more than a density capable of shieldingthe microwave (cutoff density), the microwave passing through thedielectric plate 2 is reflected by the time when it has entered into theprocessing cavity 3 by a minute distance (skin depth) from the lowersurface of the dielectric plate 2. As a result, a standing wave of themicrowave is formed in a region between the lower surface (microwaveradiating surface) of the radial line slot antenna 6 and a surface(microwave reflecting surface) formed by the reflecting ends of themicrowave. After that, the microwave reflecting surface becomes a plasmaexciting surface, and a stable plasma is excited on the plasma excitingsurface.

Therefore, it is thinkable that when the electron density in a plasmabecomes equal to or more than the cutoff density, the density of aplasma generated in the processing cavity 3 is influenced by a standingwave formed between the lower surface of the radial line slot antenna 6and the plasma exciting surface. The applicants of the present inventionhave thought that the density of a plasma generated in the processingcavity 3 can be heightened by appropriately setting the distance betweenthe lower surface of the radial line slot antenna 6 and the lowersurface of the dielectric plate 2 so as to form a favorable standingwave in the region between the under surface of the radial line slotantenna 6 and the plasma exciting surface.

That is, in the conventional RLSA plasma processing apparatus, thedistance between the lower surface of the radial line slot antenna 6 andthe lower surface of the dielectric plate 2 is set independently of thewavelength of the microwave. In the plasma nitriding apparatus (plasmaprocessing apparatus) according to the present invention, on the otherhand, the distance d1 between the lower surface of the radial line slotantenna 6 and the upper surface of the dielectric plate 2 and thethickness d2 of the dielectric plate 2 are set in such a manner that thedistance D between the lower surface of the radial line slot antenna 6and the lower surface (capable of being regarded substantially as theplasma exciting surface) of the dielectric plate 2, which is representedwith the wavelength of the microwave being a distance unit, is equal toapproximately ½. In this embodiment, for example, the distance d1between the lower surface of the radial line slot antenna 6 and theupper surface of the dielectric plate 2 is set to be 6 mm and thethickness d2 of the dielectric plate 2 is set to be 30 mm.

Letting the wavelength of the microwave in the air be λ₀ and letting thewavelength of the microwave in the dielectric plate 2 be λ, the distanceD between the lower surface of the radial line slot antenna 6 and thelower surface of the dielectric plate 2 is represented by the followingformula (1) with the wavelength of the microwave being a distance unit.D=(d1/λ₀)+(d2/λ)  (1)

Letting the dielectric constant of the dielectric plate 2 be ∈γ, thewavelength λ in the dielectric plate 2 is represented by the followingformula (2).λ=λ₀√{square root over (∈γ)}  (2)

Therefore, the above-mentioned distance D can be represented by thefollowing formula (3).D=(d1+d2√{square root over (∈γ)})/λ₀  (3)

Consequently, by substituting the dielectric constant ∈γ=3.9 of thedielectric plate 2 made of quartz and the wavelength λ₀=122 (mm) in theair (in the vacuum) of the microwave having a wavelength of 2.45 GHzinto the above-mentioned formula (3), it can be recognized that thedistance D between the lower surface of the radial line slot antenna 6and the lower surface of the dielectric plate 2, which is representedwith the wavelength of the microwave being a distance unit, is set to beapproximately 0.53.

FIG. 3 is a graph showing the density distributions of ion currentincident on the surface of a semiconductor wafer (a) when the thicknessd2 of the dielectric plate 2 is set to be 30 mm and (b) when thethickness d2 of the dielectric plate 2 is set to be 20 mm (in the caseof the conventional apparatus). Each of the line graphs (a), (b) showsthe result of examination of the ion current density distribution in aplasma excited by introducing a microwave having a frequency of 2.45 GHzand an electric power of 1200 W into a radial line slot antenna 6 withthe distance d1 between the lower surface of the radial line slotantenna 6 and the upper surface of the dielectric plate 2 being set tobe 6 mm, the distance between the lower surface of the dielectric plate2 and the surface of the semiconductor wafer W being set to be 65 mm,and the air pressure in the processing cavity 3 being set to be 66.5 Pa.

By comparing the line graphs (a), (b) in FIG. 3 with each other, it isunderstood that the ion current density (plasma density) on thesemiconductor wafer W in the case of the thickness d2 of the dielectricplate 2 being set to be 30 mm is lager than that in the case of thethickness d2 of the dielectric plate 2 being set to be 20 mm.

However, in the case of the thickness d2 of the dielectric plate 2 beingset to be 20 mm, the ion current density distribution on the surface ofthe semiconductor wafer W is substantially uniform, and on the otherhand, in the case of the thickness d2 of the dielectric plate 2 beingset to be 30 mm, the ion current incident in a region near the center ofthe semiconductor wafer W is larger than that incident in a region nearthe periphery of the semiconductor wafer W, so that the ion currentdensity distribution is not uniform in a plane.

Therefore, in this embodiment, the density distribution of the ioncurrent incident on the surface of the semiconductor wafer W isuniformized by closing a part of the slot pairs P formed in the lowersurface of the radial line slot antenna 6 to control the strengthdistribution of the microwave incident on the surface of semiconductorwafer W. In concrete, by closing ⅙ or ⅓ of the slot pairs arranged inthe outermost peripheral part of the lower surface of the radial lineslot antenna 6, the density distribution of the ion current incident onthe surface of the semiconductor wafer W is uniformized.

In the above-mentioned description, “closing ⅙ of the slot pairs” meansto close one slot pair P per six slot pairs P arranged in the peripheraldirection, and “closing ⅓ of the slot pairs” means to close one slotpair P per three slot pairs P arranged in the peripheral direction.

FIG. 4 is a graph showing the density distributions of ion currentincident on the surface of a semiconductor wafer W (a) in the case ofnot closing any slot pair P, (b) in the case of closing ⅙ of the slotpairs P arranged in the outermost peripheral part, and (c) in the caseof closing ⅓ of the slot pairs P arranged in the outermost peripheralpart. Each of the line graphs (a), (b), (c) shows the result ofexamination of the ion current density distribution in a plasma excitedby introducing a microwave having a frequency of 2.45 GHz and anelectric power of 1200 W into a radial line slot antenna 6 with thedistance d1 between the lower surface of the radial line slot antenna 6and the upper surface of the dielectric plate 2 being set to be 6 mm,the thickness d2 of the dielectric plate 2 being set to be 30 mm, thedistance between the lower surface of the dielectric plate 2 and thesurface of the semiconductor wafer W being set to be 65 mm, and the airpressure in the processing cavity 3 being set to be 66.5 Pa.

From this FIG. 4, it is understood that the density distribution of theion current incident on the surface of the semiconductor wafer W isuniformized by closing ⅙ or ⅓ of the slot pairs P arranged in theoutermost peripheral part of the lower surface of the radial line slotantenna 6.

As above-mentioned, in this embodiment, a high density plasma generationin the processing cavity 3 can be achieved by appropriately setting thedistance d1 between the lower surface of the radial line slot antenna 6and the upper surface of the dielectric plate 2 and the thickness d2 ofthe dielectric plate 2 in such a manner that the distance D between thelower surface of the radial line slot antenna 6 and the lower surface ofthe dielectric plate 2, which is represented with the wavelength of themicrowave being a distance unit, becomes approximately ½. Accordingly,this plasma nitriding apparatus can be favorably used for applyingnitriding process to a surface of a semiconductor wafer W to manufacturea semiconductor device.

Further, in this embodiment, by closing a part of the slot pairs Pformed in the lower surface of the radial line slot antenna 6 to controlthe strength distribution of a microwave radiated from the radial lineslot antenna 6, the uniformization of the density distribution of ioncurrent incident on the surface of a semiconductor wafer W held on thewafer stage 4 as well as the heightening of the ion current density(plasma density) can be achieved. Thereby, it is possible to apply asubstantially uniform plasma nitriding process to a surface of asemiconductor wafer W in a shorter time than that by a conventionalapparatus.

In this embodiment, the dielectric plate 2 is made of quartz, and thedistance d1 between the lower surface of the radial line slot antenna 6and the upper surface of the dielectric plate 2 is set to be 6 mm, withthe thickness d2 of the dielectric plate 2 being set to be 30 mm.However, the dielectric plate 2 may be made of a dielectric materialother than quartz such as alumina (Al₂O₃) or aluminum nitride (AlN).Further, the values of the above-mentioned distance d1 and the thicknessd2 may be appropriately changed. For example, there is a case in whichthe dielectric plate 2, made of a material having a large heatconductivity, efficiently transfers heat generated by the re-coupling ofions and electrons in a plasma to the chamber wall, and thereby theradial line slot antenna 6 can be prevented from being heated to a hightemperature. In this case, with the distance d1 between the lowersurface of the radial line slot antenna 6 and the upper surface of thedielectric plate 2 being preferably set to be 0 mm, the radial line slotantenna 6 may be in contact with the dielectric plate 2.

Now, shown in the following TABLE 1 are examples of the materials of thedielectric plate 2 and the combinations of the above-mentioned distanced1 and the thickness d2 for making the distance D between the lowersurface of the radial line slot antenna 6 and the lower surface of thedielectric plate 2, which is represented with the wavelength of themicrowave being a distance unit, approximately ½.

TABLE 1 material of dielectric plate distance d1 thickness d2 quartz 0mm 30.9 mm (dielectric constant = 3.9) 1.8 mm 30 mm aluminum nitride 0mm 20.6 mm (dielectric constant = 8.8) 4.6 mm 19 mm alumina 0 mm 19.5 mm(dielectric constant = 9.8) 4.7 mm 18 mm

Further, in this embodiment, it is described that the distance d1between the lower surface of the radial line slot antenna 6 and theupper surface of the dielectric plate 2 and the thickness d2 of thedielectric plate 2 are preferably set in such a manner that the distanceD between the lower surface of the radial line slot antenna 6 and thelower surface of the dielectric plate 2, which is represented with thewavelength of the microwave being a distance unit, becomes approximately½. However, the above-mentioned distance d1 and the thickness d2 may beset in such a manner that the above-mentioned distance D becomes anintegral multiple of approximately ½. Furthermore, the above-mentioneddistance d1 and the thickness d2 may be set in such a manner that theabove-mentioned distance D becomes an integral multiple of approximately¼.

That is, for the purpose of forming a favorable standing wave in theregion between the lower surface of the radial line slot antenna 6 andthe plasma exciting surface to generate a high density plasma in theprocessing cavity 3, the distance D between the lower surface of theradial line slot antenna 6 and the lower surface of the dielectric plate2, which is represented with the wavelength of the microwave being adistance unit, has only to satisfy the inequality0.7×n/4≦D≦1.3×n/4 (n being a natural number).

Further, the present invention can be embodied in other forms. Forexample, in the above-mentioned embodiment, a plasma nitriding apparatusis described as an example, the present invention is not limited to sucha plasma nitriding apparatus but can be widely applied to apparatus forplasma processing an object to be processed, for example, a plasma CVD(Chemical Vapor Deposition) apparatus, a plasma ashing apparatus, aplasma etching apparatus, a plasma oxidizing apparatus and the like.

When the present invention is applied to a plasma CVD apparatus, forexample, Ar/SiH₄, TEOS/O₂ or the like can be used as a process gas.Further, when the present invention is applied to a plasma ashingapparatus, for example, O₂, Ar/O₂, Kr/O₂ or the like can be used as aprocess gas. Further, when the present invention is applied to a plasmaetching apparatus, for example, Cl₂, HBr or the like can be used as aprocess gas (etching gas). Furthermore, when the present invention isapplied to a plasma oxidizing apparatus, for example, Kr/O₂ , Ar/O₂orthe like can be used as a process gas.

Although the present invention has been described and illustrated indetail, it is clearly understood that the same is by way of illustrationand example only and is not to be taken by way of limitation, the spiritand scope of the present invention being limited only by the terms ofthe appended claims.

This application corresponds to the Japanese Patent ApplicationNo.2000-156535 filed in the Japanese Patent Office on May 26, 2000, andthe whole disclosure of the Japanese application is incorporated hereinby reference.

1. A plasma processing apparatus for processing an object using aplasma, comprising: a processing chamber defining a processing cavityfor containing an object to be processed and a process gas therein; amicrowave radiating antenna having a microwave radiating surface forradiating a microwave in order to excite a plasma in the processingcavity; and a dielectric body provided so as to be opposed to themicrowave radiating surface; wherein no additional microwave radiatingantenna is placed between the microwave radiating antenna and thedielectric body; wherein a distance D between the microwave radiatingsurface and a surface of the dielectric body facing away from themicrowave radiating surface, which is represented with a wavelength ofthe microwave being a distance unit, is determined to be in a rangesatisfying an inequality0.7×n/4≦D≦1.3×n/4 (n being a natural number); whereby a standing wave ofthe microwave is formed between the microwave radiating surface and aplasma exciting surface, thereby exciting a plasma at the plasmaexciting surface by being supplied with energy from the standing wave ofthe microwave, the plasma exciting surface substantially coinciding withthe surface of the dielectric body facing away from the microwaveradiating surface, the plasma being formed between the plasma excitingsurface and the object to be processed, the standing wave not enteringthe plasma, wherein one end of the standing wave is positioned on theplasma exciting surface.
 2. A plasma processing apparatus for processingan object using a plasma, comprising: a process chamber defining aprocessing cavity for containing an object to be processed and a processgas therein; a microwave radiating antenna having a microwave radiatingsurface for radiating a microwave in order to excite a plasma in theprocessing cavity; and a dielectric body provided so as to be opposed tothe microwave radiating surface; wherein no additional microwaveradiating antenna is located between the microwave radiating antenna andthe dielectric body; wherein a distance D between the microwaveradiating surface and a surface of the dielectric body facing away fromthe microwave radiating surface, which is represented with a wavelengthof the microwave being a distance unit, is determined to be in a rangesatisfying an inequality0.7×n/2≦D≦1.3×n/2 (n being a natural number); whereby a standing wave ofthe microwave is formed between the microwave radiating surface and aplasma exciting surface, thereby exciting a plasma at the plasmaexciting surface by being supplied with energy from the standing wave ofthe microwave, the plasma exciting surface substantially coinciding withthe surface of the dielectric body facing away from the microwaveradiating surface, the plasma being formed between the plasma excitingsurface and the object to be processed, the standing wave not enteringthe plasma, wherein one end of the standing wave is positioned on theplasma exciting surface.
 3. The plasma processing apparatus as claimedin claim 1, in which the dielectric body is a plate-shaped memberdisposed in such a manner that a distance between the dielectric plateand the plasma radiating surface is substantially zero, and a thicknessd of the dielectric plate represented with the wavelength of themicrowave being a distance unit is determined to be in a rangesatisfying an inequality0.7×n/4≦d≦1.3×n/4 (n being a natural number).
 4. The plasma processingapparatus as claimed in claim 2, in which the dielectric body is aplate-shaped member disposed in such a manner that a distance betweenthe dielectric plate and the plasma radiating surface is substantiallyzero, and a thickness d of the dielectric plate represented with thewavelength of the microwave being a distance unit is determined to be ina range satisfying an inequality0.7×n/2≦d≦1.3×n/2 (n being a natural number).
 5. The plasma processingapparatus as claimed in claim 1, in which the microwave radiatingantenna is a radial line slot antenna having a number of slots formedand distributed in the microwave radiating surface thereof for radiatingthe microwave.
 6. The plasma processing apparatus according to claim 1,wherein the microwave radiating antenna is a radial line slot antennahaving a number of slots formed and distributed in the microwaveradiating surface thereof for radiating the microwave, the number of theslots being concentrically arranged in the microwave radiating surface;and wherein one per six or three slots in the peripheral direction ofthe slots arranged in the outermost peripheral part are closed so as touniformize, in a plane, the plasma generated in the processing cavity.7. A plasma processing method for processing an object using a plasma,the method comprising the steps of: putting an object to be processedand a process gas into a processing cavity defined in a processingchamber; radiating a microwave for exciting a plasma from a microwaveradiating antenna having a microwave radiating surface to the processingcavity; providing a dielectric body so as to be opposed to the microwaveradiating surface; and determining a distance D between the microwaveradiating surface and a surface of the dielectric body facing away fromthe microwave radiating surface, which is represented with a wavelengthof the microwave being a distance unit, to be in a range satisfying aninequality0.7×n/4≦D≦1.3×n/4 (n being a natural number), whereby a standing wave ofthe microwave is formed between the microwave radiating surface and aplasma exciting surface, thereby exciting a plasma at the plasmaexciting surface by being supplied with energy from the standing wave ofthe microwave, the plasma exciting surface substantially coinciding withthe surface of the dielectric body facing away from the microwaveradiating surface, the plasma being formed between the plasma excitingsurface and the object to be processed, the standing wave not enteringthe plasma, wherein one end of the standing wave is positioned on theplasma exciting surface, and wherein no additional microwave radiatingantenna is located between the microwave radiating antenna and thedielectric body.
 8. A plasma processing method for processing an objectusing a plasma, the method comprising the steps of: putting an object tobe processed and a process gas into a processing cavity defined in aprocessing chamber; radiating a microwave for exciting a plasma from amicrowave radiating antenna having a microwave radiating surface to theprocessing cavity; providing a dielectric body so as to be opposed tothe microwave radiating surface; and determining a distance D betweenthe microwave radiating surface and a surface of the dielectric bodyfacing away from the microwave radiating surface, which is representedwith a wavelength of the microwave being a distance unit, to be in arange satisfying an inequality0.7×n/2≦D≦1.3×n/2 (n being a natural number), whereby a standing wave ofthe microwave is formed between the microwave radiating surface and aplasma exciting surface, thereby exciting a plasma at the plasmaexciting surface by being supplied with energy from the standing wave ofthe microwave, the plasma exciting surface substantially coinciding withthe surface of the dielectric body facing away from the microwaveradiating surface, the plasma being formed between the plasma excitingsurface and the object to be processed, the standing wave not enteringthe plasma, wherein one end of the standing wave is positioned on theplasma exciting surface, and wherein no additional microwave radiatingantenna is located between the microwave radiating antenna and thedielectric body.
 9. The plasma processing apparatus as claimed in claim5, in which a part of the number of slots is closed so as to uniformize,in a plane, the plasma generated in the processing cavity.
 10. Theplasma processing method as claimed in claim 7, in which the microwaveradiating antenna is a radial line slot antenna having a number of slotsformed and distributed in the microwave radiating surface thereof forradiating the microwave.
 11. The plasma processing method as claimed inclaim 10, further comprising: a step of closing a part of the number ofslots so as to uniformize, in a plane, the plasma generated in theprocessing cavity.
 12. The plasma processing method as claimed in claim11, wherein the number of the slots are concentrically arranged in themicrowave radiating surface; and wherein the step of closing the slotsincludes the step of closing one per six or three slots in theperipheral direction of the slots arranged in the outermost peripheralpart.
 13. A plasma processing apparatus for processing an object using aplasma, comprising: a processing chamber defining a processing cavityfor containing an object to be processed and a process gas therein; amicrowave radiating antenna having a microwave radiating surface forradiating a microwave in order to excite a plasma in the processingcavity, the microwave radiating antenna being a radial line slot antennahaving a number of slots formed and distributed in the microwaveradiating surface; and a dielectric body provided so as to be opposed tothe microwave radiating surface, wherein no additional microwaveradiating antenna is located between the microwave radiating antenna andthe dielectric body; wherein a distance D between the microwaveradiating surface and a surface of the dielectric body facing away fromthe microwave radiating surface, which is represented with a wavelengthof the microwave being a distance unit, is determined to be in a rangesatisfying an inequality0.7×n/4≦D≦1.3×n/4 (n being a natural number), wherein one end of thestanding wave is positioned on the plasma exciting surface.
 14. A plasmaprocessing apparatus for processing an object using a plasma,comprising: a processing chamber defining a processing cavity forcontaining an object to be processed and a process gas therein; amicrowave radiating antenna having a microwave radiating surface forradiating a microwave in order to excite a plasma in the processingcavity, the microwave radiating antenna being a radial line slot antennahaving a number of slots formed and distributed in the microwaveradiating surface; and a dielectric body provided so as to be opposed tothe microwave radiating surface, wherein no additional microwaveradiating antenna is located between the microwave radiating antenna andthe dielectric body; wherein a distance D between the microwaveradiating surface and a surface of the dielectric body facing away fromthe microwave radiating surface, which is represented with a wavelengthof the microwave being a distance unit, is determined to be in a rangesatisfying an inequality0.7×n/2≦D≦1.3×n/2 (n being a natural number), wherein one end of thestanding wave is positioned on the plasma exciting surface.
 15. Theplasma processing apparatus as claimed in claim 13, in which thedielectric body is a plate-shaped member disposed in such a manner thata distance between the dielectric plate and the plasma radiating surfaceis substantially zero, and a thickness d of the dielectric platerepresented with the wavelength of the microwave being a distance unitis determined to be in a range satisfying an inequality0.7×n/4≦d≦1.3×n/4 (n being a natural number).
 16. The plasma processingapparatus as claimed in claim 14, in which the dielectric body is aplate-shaped member disposed in such a manner that a distance betweenthe dielectric plate and the plasma radiating surface is substantiallyzero, and a thickness d of the dielectric plate represented with thewavelength of the microwave being a distance unit is determined to be ina range satisfying an inequality0.7×n/2≦d≦1.3×n/2 (n being a natural number).
 17. The plasma processingapparatus according to claim 13, in which a part of the number of slotsis closed so as to unifomize, in a plane, the plasma generated in theprocessing cavity.
 18. The plasma processing apparatus according toclaim 13, in which the number of the slots are concentrically arrangedin the microwave radiating surface.
 19. The plasma processing apparatusaccording to claim 18, wherein one per six or three slots in theperipheral direction of the slots arranged in the outermost peripheralpart are closed so as to uniformize, in a plane, the plasma generated inthe processing cavity.
 20. A plasma processing method for processing anobject using a plasma, the method comprising the steps of: putting anobject to be processed and a process gas into a processing cavitydefined in a processing chamber; radiating a microwave for exciting aplasma from a microwave radiating antenna having a microwave radiatingsurface to the processing cavity, the microwave radiating antenna beinga radial line slot antenna having a number of slots formed anddistributed in the microwave radiating surface; providing a dielectricbody so as to be opposed to the microwave radiating surface; anddetermining a distance D between the microwave radiating surface and asurface of the dielectric body facing away from the microwave radiatingsurface, which is represented with a wavelength of the microwave being adistance unit, to be in a range satisfying an inequality0.7×n/4≦D≦1.3×n/4 (n being a natural number), wherein one end of thestanding wave is positioned on the plasma exciting surface, and whereinno additional microwave radiating antenna is placed between themicrowave radiating antenna and the dielectric body.
 21. A plasmaprocessing method for processing an object using a plasma, comprisingthe steps of: putting an object to be processed and a process gas into aprocessing cavity defined in a processing chamber; radiating a microwavefor exciting a plasma from a microwave radiating antenna having amicrowave radiating surface to the processing cavity, the microwaveradiating antenna being a radial line slot antenna having a number ofslots formed and distributed in the microwave radiating surface;providing a dielectric body so as to be opposed to the microwaveradiating surface; and determining a distance D between the microwaveradiating surface and a surface of the dielectric body facing away fromthe microwave radiating surface, which is represented with a wavelengthof the microwave being a distance unit, to be in a range satisfying aninequality0.7×n/2≦D≦1.3×n/2 (n being a natural number), wherein one end of thestanding wave is positioned on the plasma exciting surface, and whereinno additional microwave radiating antenna is placed between themicrowave radiating antenna and the dielectric body.
 22. The plasmaprocessing method as claimed in claim 20, further comprising: a step ofclosing a part of the number of slots so as to uniformize, in a plane,the plasma generated in the processing cavity.
 23. The plasma processingmethod as claimed in claim 22, wherein the number of the slots areconcentrically arranged in the microwave radiating surface; and whereinthe step of closing the slots includes the step of closing one per sixor three slots in the peripheral direction of the slots arranged in theoutermost peripheral part.